The present invention is directed in general to a method and apparatus for drilling or penetrating hard surfaces and materials such as rock, concrete and steel. In particular, the present invention is directed to penetrating hard surfaces and materials utilizing a high velocity gun system that fires multiple shots of a projectile and an energetic slurry at the surface of the material to be penetrated.
Conventional excavation techniques employ the use of drills to drill holes in a layer of a material to be penetrated. Explosives are placed in the holes and detonated to cause a layer of the material to fracture and break apart. The resulting rubble is cleared from the excavation site and the process is repeated for a subsequent layer of material to be penetrated. Such conventional excavation techniques result in a slow and tedious process in which several distinct and separate steps must be performed in sequence to excavate each layer of material to be removed.
Convention drilling or boring techniques employ the use of complicated mechanical drilling apparatus. The drilling apparatus incorporates the use of a drill bit to cut through the material being bored. Mechanical drill bits are subject to wear and breakage, however, and therefore must be periodically maintained or replaced. The required maintenance of mechanical drilling apparatus generally increases in proportion to the hardness of the material to be drilled, causing delays and interruptions in the drilling process in order to service the drilling equipment.
In view of the above, it would be desirable to provide a method and apparatus for boring through and excavating hard materials such as rock, concrete and steel that would allow for the rapid removal of material without requiring the separate steps of drilling, placement of explosives, detonation of explosives and debris removal associated with conventional excavation techniques or the use of maintenance prone and mechanically complicated drilling systems associated with conventional drilling or boring techniques.
The invention provides a method and apparatus for drilling and penetrating hard materials utilizing a high velocity gun system that fires multiple shots of a projectile and an energetic slurry at the surface of the material to be penetrated. More specifically a penetrating device is provided that includes one or more firing barrels. The firing barrels are loaded with a propellant, a projectile and an energetic (explosive) slurry, and are controlled to fire in a preselected firing sequence. The projectile enters the material to be penetrated generating a hole into which the energetic slurry is also fired. The energetic slurry detonates upon contact with the material causing an explosion that further fractures the material and which blows the material out of the hole. The process is repeated until a desired penetration is obtained.
In preferred embodiments, the projectile includes aluminum which reacts with the slurry to further enhance the explosive force, the slurry preferably includes at least one of HMX, RDX and TNT, and the propellant is a preferably a liquid propellent of a type used in conventional liquid propellant guns although conventional solid propellents may be employed. Still further, the device is preferably provided with an explosive payload that is detonated when the desired penetration depth is reached. In a still further embodiment, the device is fitted with control fins and a guidance system for use as an air launched munitions.
Additional features and advantages of the invention will become apparent to those of ordinary skill in the art after review of the following detailed description of the preferred embodiments of the invention with reference to the accompanying drawings.